The present invention relates to endoscopic devices and in particular to a fiber optic endoscope embodying a "flying spot" fiber(s).
The transmission of light through thin fibers of glass or plastics have permitted a variety of instruments for the visualization of otherwise inaccessible organs and tissues inside the human body. Such instruments are broadly referred to as endoscopes and have been useful in the diagnosis and treatment of, for example, gastro intestinal and respiratory diseases.
In recent years, thin, flexible optical fibers have allowed for the remote viewing, photography, biopsy and surgery of organs and tissues. Such thin, flexible optical fibers, also known as fiber optics, are incorporated in endoscopes to enable the transmission of light to illuminate the internal space being viewed and/or enabling the object so illuminated to be viewed. Generally, the viewing capability is accomplished by aligning multiple fibers so that the relative position of each fiber is the same at each end of the bundle. The methods and apparatus transmitting images thereon is well known.
In addition to light and image transmission, endoscopes frequently have auxiliary channels through which fluids can pass, either to or from the observation site or through which implements and tools can be remotely controlled. In addition to the above, fiber optics are used in guiding laser radiation for applications in surgery, fluorescent methods of diagnosis and high intensity illumination. The fiber optics and endoscopes have also been applied to the development of a variety of transducers for the measurement and monitoring of parameters, such as blood flow, temperature, pressure and the like.
Recent developments have involved the use of fiber optics in an endoscope known as a cardioscope to allow for the visualization of intracardial structures. This field, better known as angioscopy, may be defined as the technique for visualization of the inner surfaces of blood vessels by means of the cardioscope. Since its introduction, advances in the use of the cardioscope have enabled the fiber optics to be inserted into arteries and vessels to enable visualization. Flexible fiber optic scopes have also been recently used to beam laser energy and to observe orifices in the coronary arteries of patients.
Because of these advances in the application of endoscopes, there is a continuing need to develop fiber optics of very small diameter which are nevertheless capable of performing all of the above-described functions. Typical endoscopes presently include a bundle of fiber optics, each having a light transmitting core and an outer cladding. The light enters the end of the core and through internal reflections passes down the core to the other end. A multiplicity of such fiber optics may be gathered together in a bundle along which light passes to illuminate the object at the distal end of the endoscope. A second bundle, arranged in a coherent manner, may also be incorporated to provide a means of viewing the illuminated area at the distal end of the endoscope. Various other channels, as described above, may be provided for the transmission of fluids, the control of miniature tools or surgical instruments or any other desired function. The illuminating bundle, the visualizing bundle and the auxiliary channels are gathered together in a multi-lumen or hollow cylindrical sheath. The sheath necessarily has a thickness which increases the thickness and bulkiness of the endoscope, often preventing its use in smaller vessels of the body. The resolution of a fiber optic endoscope is limited by the core-to-core spacing. Below a certain spacing, cross talk degrades the image. Even above the theoretical fundamental limit there are practical problems in manufacturing a `loose fiber` endoscope with a spacing of less than seven (7) microns. Therefore, it is desired to make an endoscope which has a decreased diameter to thereby increase the application of the endoscope in examining increasingly smaller blood vessels and for other uses as well. The present invention provides an endoscope of for example 0.5 to 2 microns effective fiber spacing.
It accomplishes this by using a multi-fiber whose adjacent cores are phase mismatched, a flying spot fiber(s) or a flying spot multi-fiber.
My invention, in a preferred embodiment, is a fiber optic endoscope which comprises a flying spot optic imaging device having fiber optic means to illuminate an object to be viewed and to view the object illuminated. The fiber optic has a proximal end and a distal end. Means to display the object viewed is in communication with the proximal end. A lens is in optical communication with the distal end. Means are provided to impart to the fiber optic, a scanning mode, which may be in the form of a X, Y raster, a spiral scan, an oscillating scan and/or a rotary scan.
In the preferred embodiment of the invention, the fiber optic comprises a multi-fiber and the fibers scan by movement of the fibers themselves. The object lens is substantially spherical. The output signal may be converted to a standard TV signal and displayed.